/*

 * newscn.c - implementation of the elf_newscn(3) function.

 * Copyright (C) 1995 - 2006 Michael Riepe

 * 

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 * 

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Library General Public License for more details.

 * 

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <private.h>

#ifndef lint

static const char rcsid[] = "@(#) $Id: newscn.c,v 1.12 2006/07/07 22:17:01 michael Exp $";

#endif /* lint */

int

_elf_update_shnum(Elf *elf, size_t shnum) {

    size_t extshnum = 0;

    Elf_Scn *scn;

    elf_assert(elf);

    elf_assert(elf->e_ehdr);

    scn = elf->e_scn_1;

    elf_assert(scn);

    elf_assert(scn->s_index == 0);

    if (shnum >= SHN_LORESERVE) {

	extshnum = shnum;

	shnum = 0;

    }

    if (elf->e_class == ELFCLASS32) {

	((Elf32_Ehdr*)elf->e_ehdr)->e_shnum = shnum;

	scn->s_shdr32.sh_size = extshnum;

    }

#if __LIBELF64

    else if (elf->e_class == ELFCLASS64) {

	((Elf64_Ehdr*)elf->e_ehdr)->e_shnum = shnum;

	scn->s_shdr64.sh_size = extshnum;

    }

#endif /* __LIBELF64 */

    else {

	if (valid_class(elf->e_class)) {

	    seterr(ERROR_UNIMPLEMENTED);

	}

	else {

	    seterr(ERROR_UNKNOWN_CLASS);

	}

	return -1;

    }

    elf->e_ehdr_flags |= ELF_F_DIRTY;

    scn->s_shdr_flags |= ELF_F_DIRTY;

    return 0;

}

static Elf_Scn*

_makescn(Elf *elf, size_t index) {

    Elf_Scn *scn;

    elf_assert(elf);

    elf_assert(elf->e_magic == ELF_MAGIC);

    elf_assert(elf->e_ehdr);

    elf_assert(_elf_scn_init.s_magic == SCN_MAGIC);

    if (!(scn = (Elf_Scn*)malloc(sizeof(*scn)))) {

	seterr(ERROR_MEM_SCN);

	return NULL;

    }

    *scn = _elf_scn_init;

    scn->s_elf = elf;

    scn->s_scn_flags = ELF_F_DIRTY;

    scn->s_shdr_flags = ELF_F_DIRTY;

    scn->s_freeme = 1;

    scn->s_index = index;

    return scn;

}

Elf_Scn*

_elf_first_scn(Elf *elf) {

    Elf_Scn *scn;

    elf_assert(elf);

    elf_assert(elf->e_magic == ELF_MAGIC);

    if ((scn = elf->e_scn_1)) {

	return scn;

    }

    if ((scn = _makescn(elf, 0))) {

	elf->e_scn_1 = elf->e_scn_n = scn;

	if (_elf_update_shnum(elf, 1)) {

	    free(scn);

	    elf->e_scn_1 = elf->e_scn_n = scn = NULL;

	}

    }

    return scn;

}

static Elf_Scn*

_buildscn(Elf *elf) {

    Elf_Scn *scn;

    if (!_elf_first_scn(elf)) {

	return NULL;

    }

    scn = elf->e_scn_n;

    elf_assert(scn);

    if (!(scn = _makescn(elf, scn->s_index + 1))) {

	return NULL;

    }

    if (_elf_update_shnum(elf, scn->s_index + 1)) {

	free(scn);

	return NULL;

    }

    elf->e_scn_n = elf->e_scn_n->s_link = scn;

    return scn;

}

Elf_Scn*

elf_newscn(Elf *elf) {

    Elf_Scn *scn;

    if (!elf) {

	return NULL;

    }

    elf_assert(elf->e_magic == ELF_MAGIC);

    if (!elf->e_readable && !elf->e_ehdr) {

	seterr(ERROR_NOEHDR);

    }

    else if (elf->e_kind != ELF_K_ELF) {

	seterr(ERROR_NOTELF);

    }

    else if (!elf->e_ehdr && !_elf_cook(elf)) {

	return NULL;

    }

    else if ((scn = _buildscn(elf))) {

	return scn;

    }

    return NULL;

}